One type of semiconductor package includes several semiconductor components in a single package module. The semiconductor components can be in the form of semiconductor dice, semiconductor packages, or semiconductor wafers. This type of package is sometimes referred to as a multi chip module (MCM) package, or as a system in a package (SIP).
Typically, the MCM package is constructed to provide a system level of functionality, such as a control or memory function. As such, the MCM package can include different types of semiconductor components configured to perform different functions in the system. For example, a MCM package configured as a micro controller can include a microprocessor component, and one or more memory components, such as SRAMs, DRAMs, or flash memories.
MCM packages offer increased system performance, because the integrated circuits on the semiconductor components can be operated more efficiently. This is largely a result of decreasing the interconnection length between the components. In addition, system performance is improved because the input/output ports for the MCM package can be configured to access the whole system, which can be organized to reduce signal delays and access times. The power requirements are also reduced due to a reduction in the driver requirements.
One problem that occurs in the MCM packages results from parasitic inductance. For example, parasitic inductance can result from switching transients and cross coupling between the conductors (e.g., wires or traces) that electrically connect the different components in the MCM package. Parasitic inductance can cause transient voltages, spurious signals, and power supply noise, which degrade the operation of the semiconductor components, and adversely affect the performance of the system. Parasitic inductance can also make testing of the MCM packages more difficult because false readings are obtained, making electrical evaluation of the packages more difficult. Parasitic inductance is particularly a problem at clocking speeds of 500 mHz or more.
One technique for overcoming parasitic inductance is by filtering the transient voltages, spurious signals and power supply noise. For example, external decoupling capacitors can be surface mounted within the MCM packages or on a substrate, such as a circuit board or test board, containing the MCM packages. One problem with these external capacitors is that they are susceptible to shorting, and also to mechanical damage due to their surface mounting. In addition, the conductive paths between the capacitors and the components, or the integrated circuits on the components, can also produce parasitic inductance. As MCM packages, and other systems containing multiple semiconductor components, become more densely populated with components, problems associated with parasitic inductance are increased.
The present invention reduces the problems associated with parasitic inductance by incorporating an on board capacitor into the structure of a component. In addition, the on board capacitor is more durable than conventional surface mount capacitors, is protected by the structure of the component, and is closer to the integrated circuits contained on the component. The present invention is also directed to a novel method for fabricating components with on board capacitors, and to improved systems incorporating the components.